from bisect import *
N = int(input())
A = list(map(int, input().split()))
Q = {A[0]}
for a in A[1:]:
    Q2 = set()
    while Q:
        x = next(iter(Q))
        Q.remove(x)
        Q2.add(x + a)
        Q2.add(x - a)
        Q2.add(x * a)
        if a != 0:
            Q2.add(x // a)
    Q2 = sorted(list(Q2))

    Q = set()
    Q.add(Q2[0])
    Q.add(Q2[-1])
    if Q2[-1] > 0:
        Q.add(bisect_left(Q2,0))
    if Q2[0] < 0:
        Q.add(bisect_left(Q2,0) - 1)
print(max(list(Q)))